نتایج جستجو برای: entrance surface dose
تعداد نتایج: 941173 فیلتر نتایج به سال:
INTRODUCTION It is well recognized that, apart from natural background, medical exposures are at present by far the largest source of exposure to ionizing radiation of the population and that several radiation protection measures should be taken by each country to prevent unnecessary or unproductive medical radiation exposure. The main tools generally to achieve this aim are justification of pr...
Introduction:Intravenous urography (IVU) test includes high number of images and extended imaging size. These make IVU as a diagnostic method with high absorbed doses by sensitive organs such as intestine and gonads in pelvic-abdominal area. In this study absorbed doses of pelvic-abdomen sensitive organs such as Adrenal, Bladder, Colon and Gonads in IVU test. <stron...
This work investigated the possibility of using proton beam for total body irradia-tion (TBI). We hypothesized the broad-slow-rising entrance dose from a monoen-ergetic proton beam can deliver a uniform dose to patient with varied thickness. Comparing to photon-based TBI, it would not require any patient-specific com-pensator or beam spoiler. The hypothesis was first tested by simulating 250 Me...
OBJECTIVE To compare the slot-scan digital radiography (SSDR) of the lower extremity region and the computed radiography (CR) method with respect to the image quality and radiation exposure. MATERIALS AND METHODS We enrolled 54 patients who underwent both the SSDR and CR of the lower extremities. The study evaluated and statistically compared the image quality of four features (outer cortex, ...
background: radiation dose knowledge through xray examinations and their distribution in iran provides useful guidance on patient dose reduction. the results of the entrance skin dose (esds) of five common radiographies in all radiology centers in yazd province were reported in our previous study (2003). in the present study we have evaluated the collective effective dose of conventional x-ray ...
PURPOSE To compare radiation dose and image quality between a slot-scanning system (SSS) and a dynamic flat-panel detector (DFD) in assessing scoliosis in children. METHODS An experimental study was first performed with a phantom to assess the quality of each device. The clinical part included a prospective observational dosimetric and qualitative comparative study with acquisition of whole-s...
introduction: delivering maximum dose to tumor and minimum dose to normal tissues is the most important goal in radiotherapy. according to icru, the maximum acceptable uncertainty in the delivered dose compared to the prescribed dose should be lower than 5%, and this is because of the relationship between absorbed dose, tumor control and normal tissue damage. absorbed dose accuracy is investiga...
The purpose of this work is to compare computed radiography (Kodak CR 400) and film/screen combination (Speed 400) systems in regards of patient dose, technique settings, and contrast-detail detectability. A special contrast-detail phantom with drilled holes of varying diameter (detail) and varying depth (contrast) was utilized. Various thicknesses of the Lucite sheets were utilized to simulate...
The use of diagnostic reference levels (DRLs) is part of the optimisation process of radiation protection, in that it identifies practices that are in need of corrective action, resulting in dose reduction. Their use is provided for in Irish and European legislation. In this project, measurements were carried out at 42 of the 46 licensed intra-oral xray machines in Co. Wicklow using an Unfors M...
background it is remain a main concern that pediatric chest radiographies contribute to the significant radiation exposure to the thyroid gland as a more susceptible organ to radiation induced cancer. the aim of this study was to evaluate the entrance surface dose (esd) of pediatric chest radiography compared to the diagnostic reference levels (drl) and evaluation the efficacy of the lead (pb)...
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